Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system characterized by breakdown of the myelin sheath covering nerve axons. It affects over 400,000 people in the US and more than 2.1 million worldwide. Genetic factors, autoimmunity, infection, vitamin D levels, and loss of protective childhood infections may play a role in MS etiology. Clinically, MS presents with a variety of neurological symptoms depending on the location of lesions in the brain and spinal cord, including visual, motor, sensory and cognitive impairments. Disease courses include relapsing-remitting MS, secondary progressive MS, primary progressive MS and progressive-relapsing MS.